Depending on what's being done on a users network prior to the disconnect, the meters can appear to show some data loss as they aren't updated instantly, there is a slight lag-time between using the data, and any of the meters reflecting that usage.
We understand you filed a complaint with Consumer Affairs last month as well. This should have been forwarded to our corporate office and you should have gotten a reply by now. I did try to find out more from you about your concerns in your original post but never heard back. You are welcome to start a new one.
We're sorry to hear you are having data concerns again. Since we can rule out Windows 10 being the culprit, have you considered things like iCloud Drive automatically syncing? Since the bucket meter is checked by the Hughes network in intervals, the 100MB could be used during a reading interval but before you unplugged.
The easiest way to figure is out is to get some fresh data. As Gwalk mentioned, performing the test with the screenshots and posting the results here with the date/time information will help us to get started.